The present invention pertains to the art of medical diagnostic imaging and, more particularly, to a computerized tomographic (CT) scanner apparatus.
The typical CT scanner apparatus uses an X-ray source and a multiple array of X-ray detectors which are carried on opposite sides of a frame mounted for rotation about a longitudinal axis which is generally horizontally disposed. During rotation a longitudinally thin X-ray beam is projected through a subject or patient positioned on the longitudinal axis. The detectors develop signals indicative of X-ray transmission characteristics through the subject. The signals are suitably modified and/or amplified and used by a computer to control a cathode ray tube or the like for forming a reconstructed image of the layer through which the X-ray beam has passed.
Normally, the X-ray beam is projected through a thin layer of the subject's body so that the layer of the reconstructed image is perpendicular to the longitudinal axis on which the patient is disposed. In certain instances, however, the type of diagnostic information required can best be obtained by viewing a layer through the subject's body which is tilted slightly through a small vertical angle which is not perpendicular to the longitudinal axis along which the patient is positioned.
Different types of support frames and mechanisms have been proposed for providing the various rotational, translational and tilting functions discussed above. Generally, however, the prior support frames and mechanisms have been unduly complex and/or unable to satisfactorily perform the tilting function.